Did you know that fishes can live in waters with temperatures between the freezing point of salt water and over 110 degrees Fahrenheit? The characteristics of fishes relating to function, form, behavior, and ecology vary across similarly spectacular ranges, and with over 30,000 described species of fishes (representing more than half of all known vertebrates), how can this evolutionary exuberance be conveyed to a nonspecialist audience? Do Fish Sleep? Fascinating Answers to Questions about Fishes is the answer. Estuarine ecologist Judith S. Weis aims at communicating such diversity in her new book with an interdisciplinary view of how the natural history of fishes intertwines with human lives. Structured as 112 questions in eleven chapters, the book follows the model of the Rutgers University series Animal Q&A: Fascinating Answers to Questions about Animals. The editors describe the series as “covering everything from basic biology to complex behavior.” Although covering everything poses a practically impossible task for any author, Weis addresses a rich range of fish-related topics from the perspectives of biology, economics, conservation, health, and culture.
For the sake of coherence, I will use the term fishes for aquatic fishlike nontetrapod vertebrates (jawless; cartilaginous; and bony fishes, including lobbed-fin and ray-finned fishes). This grouping is strictly based on ecological premises, which seem to be the implicit criterion followed by Weis (more on this below). The book could be divided into two main parts. In the first six chapters, Weis responds to questions about evolution (How did fishes evolve?), form and function (How do fishes swim? Do fishes smell?), life habits and behavior (Do fishes build nests? And of course, do fish sleep?), and ecology (How do fishes interact with plants?), as well as to questions about their natural enemies, such as diseases, parasites, and predators.
In the second part of her book, Weis surveys nonbiological connections between fishes and human culture, economy, and health. The aesthetic and recreational lure (pun intended) of fishes is addressed with questions relative to home aquaria (Which fishes adapt well and live peacefully in a home fish tank?), swimming (What are the advantages and disadvantages of snorkeling and scuba diving?), and fishing (What is ice fishing?). Particularly refreshing are the notes on the fish theme throughout art, children's literature, and religion.
Commercial fishing, including history of the industry, targeted species, and fishing gear, is also reviewed. Weis explains how unregulated fisheries not only affect fish populations and ecosystems but also the economy. Aside from depicting this somber reality, the author includes examples of what has been done and what could be done to improve the situation. Understandably, the depth with which different topics are presented varies across chapters. Weis is at her best when writing about issues related to her own professional interests, such as estuaries, salt marshes, and the effect of mercury and other pollutants on fishes.
A major challenge in communicating science to nonspecialists is how to avoid taking for granted those concepts and ways of thinking inherent to a scientific specialty. Weis passes this test with honors, showing a special talent for explaining complex subjects in a clear and succinct way and without excessive use of jargon. Using a few select examples, Weis successfully conveys a full range of variation. One shortcoming throughout the text, though, is a lack of consistency regarding how fish species are referred to. Given the general ubiquity of common names, a consistent addition of the scientific name after the common name would have improved clarity and facilitated further research on those species.
The specialist, however, in reading a book that aims at “covering everything” about fishes, cannot avoid detecting that the presentation of certain concepts could be misleading. The evolution and the classification of fishes (addressed in chapter 1) are topics that strike me as especially daring. The problem with questions such as What is a fish? and How are fishes classified? is that the overlapping use of the concepts of fishes and classification seems a contradiction. Once Weis acknowledges that classifications are phylogeny-based, an explanation for the omission of the group fishes in the classification of fishes presented might be appropriate. A group in a phylogeny-based (cladistic) classification is required to include all the descendants from the most recent common ancestor (in this case, the ancestor of all vertebrates). Therefore, if the group fishes is accepted, it would include tetrapods. We are fish in the same way that birds are dinosaurs. (Systematists eventually got rid of the name fishes and kept the more neutral one, Vertebrata.) I am not against using the group fishes in an ecological context. I wonder, however, if Weis is not underestimating the ability of her readers to understand their own tree of life.
In addition, the mention of interesting research studies makes the process of science more real to the reader, but Weis sometimes fails to include scientists' names. I assume she also opted, for the sake of maintaining a nonacademic style, to omit citations and footnotes from the book, which I personally miss. An appendix with supporting literature is added in each chapter; however, it is not always clear which content they refer to.
The book closes with a chapter on research (Why do people study fishes?) and one on conservation (What can we do to protect fishes?), in which Weis summarizes the ethical, aesthetic, and practical reasons for caring about the future of fishes and their ecosystems. Why do we need books for the general reader like Do Fish Sleep? I believe scientists play an increasing role in eliciting public awareness and changes of attitude. Weis's new book is a valuable contribution toward that goal.